204 
Barrows on Birds of the Lower Uruguay. 
[October 
Blanca where it was occasionally seen running over the roofs of 
the houses. Of its breeding habits I know nothing, but most of 
the birds undoubtedly breed further south. 
78. Furnarius rufus Hornero (Oven-builder). ! 
— This bird has been so often and so thoroughly described that 
I do not feel like saying much about it. Its familiarity with 
man, its curiosity, its piercing notes and its strange, dome- shaped 
mud nest are all well known. At Concepcion it is one of the 
commonest residents and its nest may be seen in almost any 
street. 
The nest is built of §uch mud as can be found near at hand, 
and if the mud contain grass-roots. or similar fibres so much the 
better, but I do not think the birds worry themselves much 
about the quality of the materials. Although the eggs may not 
be laid until September or October, the birds often begin work 
on the nest as early as the middle of June, thus occupying three 
months or more in its completion. In fact I doubt if there is 
any month in the year when one cannot find Oven-birds at work 
on their nests. If the weather is dry they suspend work for a 
week or two until a shower refills the muddy pool from which 
they draw their building material, when they go on leisurely as 
before. This is the case only in winter, and when there is nothing 
to cause haste. In spring and summer the case is entirely other- 
wise ; a nest may then be begun and finished within a week. 
But a winter-built house is usually much the best, and not a 
few such withstand the rain and heat for a year or more if not 
sooner pulled down by boys, iguanas, or birds of prey. The 
clayey mud bakes almost to brick and it is no easy matter even 
to break out a hole large enough to extract the eggs. The nests 
are rather less than a foot in greatest diameter, and though the 
eggs are not visible from the entrance the common statement 
that there is an “ante-chamber” to the nest seems to me not 
quite accurate. The nest is built very much like a spiral shell, and 
if one could remove the inner whorls from such a shell as Amfu- 
laria he would have quite a fair miniature of the Hornero’s nest. 
The eggs are seldom more than three in number, and are orig- 
inally pure white, but being laid directly on the muddy floor of 
the nest they soon acquire about the same color. I have taken 
them from September 16 until January 15, but the larger 
number are, I think, laid during October. 
